This invention relates to automatic cannon, and more particularly to an automatic cannon which has many advantages compared to prior art cannons of its caliber range. The invention involves a novel mechanism by means of which separate loading ammunition may be rapidly and efficiently automatically loaded and fired. Prior art separate loading ammunition cannons have traditionally been of the semi-automatic or manual loading type. Thus this invention comprises a significant step forward in the art, in that it substantially increases firepower compared to comparable weapons in the prior art.